What are the desirable properties of a decomposition
Partition constraint.
Dependency preservation.
Redundancy.
Security.
Correct Answer :
B. Dependency preservation.
What are the desirable properties of a decomposition dependency preserving. (Lossless join and dependency preserving are the two goals of the decomposition.)
Related Questions
When an E-R diagram is mapped to tables, the representation is redundant for
weak entity sets
weak relationship sets
strong entity sets
strong relationship sets
The set of all values that can be taken by the attribute is called as _______ of the attribute.
Tuple
Cardinality
Degree
Domain
According to the levels of abstraction, the schema at the intermediate level is called
Logical schema.
Physical schema.
Subschema.
None of the above.
In 2NF
No functional dependencies (FDs) exist.
No multivalued dependencies (MVDs) exist.
No partial FDs exist.
No partial MVDs exist.
The normal form that is not necessarily dependency preserving is
2NF
3NF
BCNF
4NF
Which normal form is considered adequate for normal relational database design?
2NF
5NF
4NF
3NF
Which one is true statement :
With finer degree of granularity of locking a high degree of concurrency is possible.
Locking prevents non-serializable schedules.
Locking cannot take place at field level.
An exclusive lock on data item X is granted even if a shared lock is already held on X.
Processed data is called _____
Raw data
Source
Information
Useful data
Which of the syntax is correct for insert statement?
i) insert into values
ii) insert into (column list) values
ii) insert into
i-only
ii-only
Both of them
None of them
What will be the number of columns and rows respectively obtained for the operation, A- B, if A B are Base union compatible and all the rows of a are common to B? Assume A has 4 columns and 10 rows; and B has 4 columns and 15 rows
4,0
0,0
4,5
8,5
The graphical representation of a query is .
B-Tree
graph
Query Tree
directed graph
A list consists of last names, first names, addresses and pin codes. If all people in the list have the same last name and same pin code a useful key would be
the pin code
the last name
the compound key first name and last name
Tr from next page
Relational Algebra is
Data Definition Language .
Meta Language
Procedural query Language
None of the above
The division operator divides a dividend A of degree m+n by a divisor relation B of degree n and produces a result of degree
m - 1
m + 1
m * m
m
Tree structures are used to store data in
Network model.
Relational model.
Hierarchical model.
File based system.
Which of the following is not a property of transactions?
Atomicity
Concurrency
Isolation
Durability
The concept of mapping of ______ entity types is the concept in which the for each strong entity type E in the ER schema, create a relation R that includes all the simple attributes of E.
Regular
Irregular
None
Weak
The language that requires a user to specify the data to be retrieved without specifying exactly how to get it is
Procedural DML.
Non-Procedural DML.
Procedural DDL.
Non-Procedural DDL.
What is data integrity?
It is the data contained in database that is non redundant.
It is the data contained in database that is accurate and consistent.
It is the data contained in database that is secured.
It is the data contained in database that is shared.
operator is used to compare a value to a list of literals values that have been specified.
Like
COMPARE
BETWEEN
IN
What is a disjoint less constraint?
It requires that an entity belongs to no more than one level entity set.
The same entity may belong to more than one level.
The database must contain an unmatched foreign key value.
An entity can be joined with another entity in the same level entity set.
The values of the attribute describes a particular
Entity set
File
Entity instance
Organization
As per equivalence rules for query transformation, selection operation distributes over
Union.
Set difference.
Intersection.
All of the above.
………………… approach reduces time and effort required for design and lesser risk in database management.
Single global database
Multiple databases
Top-down approach
None of the above
In b-tree the number of keys in each node is than the number of its children.
one less
same
one more
half
If the closure of an attribute set is the entire relation then the attribute set is a
superkey
candidate key
primary key
not a key
Which of the following is not a logical database structure?
Chain
Network
Tree
Relational
The transactions like adding an employee, enrolling a student in a course are examples of _______
Logical
Physical
None
Theoretical
SQL server stores index information in the _____system table
system indexes
syst indexes
sys indexes
sysind
If two relations R and S are joined, then the non matching tuples of both R and S are ignored in
left outer join
right outer join
full outer join
inner join